Over the years there has arisen increasing concern on the part of scientists, environmentalists, and the general public as to the condition of our environment, and the adverse impact that humans have had upon it. Some of this concern has been directed toward the destruction of forests and trees which provide oxygen for our atmosphere, and toward the introduction of environmental pollutants, especially those entering surface water and eventually drinking water supplies. Pollutants can be from point sources, like a pipe, or they can be non-point sources such as runoff from fields or diffuse leakage from landfills or septic systems. Non-point source pollutants are currently a major source of contamination of American drinking water. A number of pollutants enter waterways as a result of the use of chemicals on crop land. This is especially true of nitrate-nitrogen and phosphorous used as fertilizers on crops. In agricultural states such as Iowa for example, nitrate-nitrogen is the number one pollutant of drinking water exceeding EPA-defined drinking water standards. The nitrogen fertilizers are but one of a number of chemicals that are injected in or on the soil or sprayed on crops, and then enter the near surface ground water and travel to nearby streams and therefore ultimately may reach drinking water supplies.
Once in the drinking water supply, the most commonly used method of removing such pollutants is to treat the water at treatment plants before it is presented to the general public. Often such treatment is not done due to expense for nitrate removal, resulting in public exposure of nitrate-nitrogen in the drinking water supply. This is only one example of the numerous pollutants which can enter ground water supplies causing contamination.
At the same time, conservationists seek to prevent the destruction of forests since trees provide, among other benefits, carbon dioxide uptake and oxygen production for our atmosphere as well as wildlife habitat, erosion control, and wind shelter. A variety of measures have been taken to try to encourage the planting of trees in order to obtain these advantages. However, in times of economic distress and cuts into governmentally supported conservation programs, it can be difficult to provide incentives for using valuable land to grow trees.
This invention is related to solving each of these problems in a unique and holistic way. It provides for a natural means of removing pollutants, or stabilizing such pollutants, in order to prevent them from traveling through the near surface ground water to nearby streams and ultimate drinking supplies. It does this by using particular types of trees planted in a particular manner, as below described, in order to achieve maximum removal of pollutants from near surface ground water with minimum but strategically located tree buffers. Trees have not played a major role in the management of water, air, and soil pollution caused by people, primarily because most trees grow too slowly in their early life to be used effectively for this purpose.
In addition to removing environmental pollutants, the trees may be used as a harvestable crop, providing, among other products, a renewable source of fuel, lumber, pulp, paper, or industrial chemical feed stock. This crop value provides to the land owner a quicker return on the investment of setting aside land for a tree buffer strip. By using this natural means of removing pollutants, one additionally achieves the advantages of providing a wildlife habitat, soil stabilization, a wind buffer, a sink for carbon dioxide, and a source of oxygen for the atmosphere, to say nothing of the visual enhancement provided by trees.
The method described here selects for trees with preformed root initials (members of Salicaceae family) capable of growing roots to prescribed depths; and, the manner of planting employed allows an extensive root system to reach very deep levels within the soil. In this manner, an extensive root system can reach down to the near surface ground water, and in fact grow beneath the water table (phreatic surface).
The method employed allows extensive deep root systems to grow at such levels without dying. By pre-selecting the trees, buffer location, planting them in the manner described, and harvesting them as indicated, a natural and relatively passive method of pollutant removal is achieved while at the same time providing a renewable crop, and its own source of economic return.
Accordingly it is an object of the present invention to provide a natural means of pollutant removal from near surface ground water.
Another object of the invention is to provide a renewable, sustainable crop while removing or inhibiting pollutants.
Yet another object of the invention is to provide an economical means of pollutant removal or inhibition.
A still further object of the invention is to provide for a method of pollutant removal or inhibition which additionally provides environmental benefits.
Still further objects of the invention will become apparent in the following disclosure.